The stock oiltank had 1 flat side and one rounded side, we will be mounting
the oiltank upsidedown and mirroring the round side. Aad cut off the filler
opening and I made a tape-template. The first layer is ordinary masking tape,
followed by 2 layers of glass fiber tape. This tape only can stretch in one
direction; I did 2 layers normal to eachother so the tape-template would
hold the shape after removal. We marked the positions for the welds in
marker and added markings to see how the pieces will align later.

Aad used the tape template to make the part is steel, using first the English-
wheel to give the center some "crown", then the pullmax to shrink the sides
and finally the planishing hammer to smooth and shape untill the tape-template
fit the steel part exactly. As we were mirroring the other side of the tank, the tape-
template had to be flipped insideout ofcourse. Don't ask about Aad's gloves...